Question

1) Using the bacterial DNA sequence that the instructor gave you:

a. Identify and underline the promoter region and the start codon.

b. Identify the coding and template strand

c. Transcribe the coding sequence

d. Translate the mRNA sequence

8) Which of the following mutational changes would you predict to be the most deleterious to gene function? Explain your answers.

a. Insertion of a single nucleotide near the end of the coding sequence.

b. Removal of a single nucleotide near the beginning of the coding sequence.

c. Deletion of three consecutive nucleotides in the middle of the coding sequence.

d. Deletion of four consecutive nucleotides in the middle of the coding sequence.

e. Substitution of one nucleotide for another in the middle of the coding sequence.

12) Use the following fragment of a polypeptide sequence to perform "reverse translation" to determine the mRNA sequence.

Val Asp Trp Leu Lys Gly Asn Thr

a. Compare your mRNA sequence to the sequence of at least two of your lab mates. Are they the same? Can you use more than one codon for each amino acid?

b. Perform reverse transcription using your mRNA sequence to determine the DNA from which it was transcribed?

c. Explain why the flow of genetic information could not be polypeptide → RNA → DNA?

Answer 1

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Answer c.
CGG CGA GCC AAA CUG UAG_ GGU CGA CAU CGC CGG AAU AUA AUA GGC CGG CGA UGU GGA UCG
AGG UGG AAG UUU GUU CCU UAU AGC AAC UAC AGU GAC AUA GCG GCA GAU CAA GAC GAC AGA ACA
GAG AGU ACC GGC GAC CGA CCG AAA AGA CGG UGG CGC GAC UGG UUG GAG CAG CGC CUU GGU AAG
CGA UUU GAG CUU GUC CUG AAA CCG CCG AGG UAG_ CCC GUC AUU CCG AGA CUU UUA GUA GAU
AAC CGG GUG GUG GCGAnswer d
ARG ARG ALA LYS LEU STOP GLY ARG HIS ARG ARG ASN ILE ILE GLY ARG ARG CYS GLY SER ARG TRP LYS
PHE VAL PRO TYR SER ASN TYR SER ASP ILE ALA ALA ASP GLN ASP ASP ARG THR GLU SER THR GLY ASP
ARG PRO LYS ARG ARG TRP ARG ASP TRP LEU GLU GLN ARG LEU GLY LYS ARG PHE GLU LEU VAL LEU LYS
PRO PRO ARG STOP PRO VAL ILE PRO ARG LEU LEU VAL ASP ASN ARG VAL VAL ALA
Answer 12.
VDWLKGNT
a.
Seq 1: 5’ GUU GAU UGG CUU AAA GGU AAU ACU 3’
Seq 2: GUC GAC UGG CUC AAG GGC AAC ACC
Since the Codons are Degenerate in nature hence there are possibilities of several codons
encoding the similar amino acids. Hence there are many possible sequences
b. 3’ CAA CTA ACC GAA TTT CCA TTA TGA 5’
c. Flow of genetic information cannot be from protein to RNA to DNA as one amino acid can be
coded by several codon and hence the genetic information will vary from individual to individual
which is not acceptable.
Answer 8:
Deletion of four consecutive nucleotide in the middle of the coding sequence will have most
deleterious effect as it would cause the reading frame to change which would change the sequence of
amino acids in the polypeptide chain. This would lead to translation of a non-functional protein and
waste of resources and energy for the translation of this non functional protein.

Start Site 5 Start Site Promoter Region Template Strand Cording Strand AACAAGGAATATCGTTGATGTCACTGTATCGCCGTCTAGTTCTGCTGTCTTGTCTCTCATGGCCGCTGGC TTGTTCCTTATAGCAACTACAGTGACATAGCGGCAGATCAAGACGACAGAACAGAGAGTACCGGCGACCG TGGCTTTTCTGCCACCGCGCTGACCAACCTCGTCGCGGAACCATTCGCTAAACTCGAACAGGACTTTGGC ACCGAAAAGACGGTGGCGCGACTGGTTGGAGCAGCGCCTTGGTAAGCGATTTGAGCTTGTCCTGAAACCG GGCTCCATCGGGCAGTAAGGCTCTGAAAATCATCTATTGGCCCACCACCGC 3 CCGAGGTAGCCCGTCATTCCGAGACTTTTAG TAGATAACCGGGTGGTGGCGⓟ 5. Answerc CUCUUA A CGG CGA GCC AAA CUG UAG_ GGU CGA CAU CGC CGG AAU AUA AUA GGC CGG CGA UGU GGA UCG AGG UGG AAG UUU GUU CCU UAU AGC AAC UAC AGU GAC AUA GCG GCA GAU CAA GAC GAC AGA ACA GAG AGU ACC GGC GAC CGA CCG AAA AGA CGG UGG CGC GAC UGG UUG GAG CAG CGC CUU GGU AAG CGA UUU GAG CUU GUC CUG AAA CCG CCG AGG UAG_ CCC GUC AUU CCG AGA CUU UUA GUA GAU AAC CGG GUG GUG GCG AAGG UUG GAG CAG COC CUU GGUAAG